Water insoluble disinfectant composition

ABSTRACT

There is provided a water insoluble disinfectant composition comprising a tertiary amine quaternized with a water insoluble carrier to provide a quaternary ammonium salt. 
     In the preferred modification of the invention, the carrier is a resin, most suitably a crosslinked polystyrene or crosslinked methacrylate resin. The compositions of the present invention are formed by creating an amine reactive labile active center on the carrier and reacting said activated carrier with the amine of choice to form a quaternary ammonium salt. Ammonium salts having at least one alkyl moiety of C10 to C16 carbon atoms and at least one aryl moiety have been found particularly effective.

This invention was made with Government support under NSF-SOS Project240-547A (June 1977) awarded by National Science Foundation. TheGovernment has certain rights in this invention.

This application is a division, of application Ser. No. 117,062, filed1/31/82, now U.S. Pat. No. 4,349,646.

BACKGROUND OF THE INVENTION

Heretofore chlorination has been designated as the most reliable waterdisinfection method and is liable to remain so for the foreseeablefuture. Nevertheless, in view of the presence of organic compounds inmany water sources, chlorination presents the danger of the formation oftoxic or carcinogenic substances. Work has, therefore, been directed toseeking alternative modes of drinking water disinfection. A generalalternate approach involves strong modes of oxidation for example theuse of ozone or the use of ultraviolet radiation. Another oxidizingapproach involves the use of the oxidizing power of polyhalide speciesabsorbed on strong base ion exchange resins. These polyhalidecounterions release free halogens or hypohalous acids which destroyharmful organisms. Unfortunately, the most effective of these polyhalidespecies contain iodine, e.g. in the form of the triiodide ion, which isundesirable with respect to dietary intake for certain groups of thepopulation.

A different class of compounds namely the soluble quaternary ammoniumsalts colloquially known as Quats have been suggested for emergencydisinfection of drinking water supplies and, because of their lowtoxicity for mammals, have been utilized as sanitizers in commercialapplications. Because of some inappropriate application of Quats,despite their apparent combination of effectiveness and harmlessnessthey have fallen into disrepute among medical practitioners, and are nownot utilized for the emergency disinfection of drinking water supplies.

It has been postulated that if the soluble Quats could be insolubilizedin a procedure which involved stable chemical bonding to an insolublecarrier while retaining their disinfectant qualities a desirable productmight be obtained.

SUMMARY OF THE INVENTION

The present invention comprises the provision of stable, water insolublequaternary ammonium salts. For the sake of convenience thesecompositions will be discussed with respect to the amine portion and thecarrier portion used in the formation of these compositions. As will beseen in the discussion of the preferred embodiments, however, chemicallyspeaking an interchangeability of groups in fact exists. The novelcompositions of the present invention are produced by activating acarrier, for example polymeric resin, to provide a labile center thereonwhich will react with a tertiary or bistertiary amine to provide astable, water insoluble, quaternary ammonium salt. The anion of saidsalt may be the anion of any physiologically acceptable acid. Such adesignation is one of desirability rather than criticality since the"anion leakage" of these compounds is minimal.

The compositions of the present invention have the following generalstructure: ##STR1##

R₁ and R₂ are alkyl, alkenyl or cycloalkyl or, taken with the nitrogento which they are attached are a heterocycle. R₃ where present is alkyl,alkaryl, aralkyl or aryl, Q is the carrier moiety bonded to the ammoniumnitrogen, a is an integer corresponding to the number of ammoniummoieties per carrier moiety, x is the counterion of any physiologicallyacceptable acid having valence n, wherein n is an integer. Any one of R₁R₂ or R₃ may itself represent a quaternary ammonium moiety of thesubstructure ##STR2## wherein R₄ and R₅ may have any of the values ofR₁, R₂ or R₃ and y is an integer of 1-20.

It will be understood by those skilled in the art that where R₁ and R₂form a fully unsaturated heterocycle with the nitrogen to which they areattached, R₃ cannot be present.

The modification of this invention where the carrier was ahalomethylated polystyrene (crosslinking not shown) may be shown as##STR3## wherein a and n are as above and n is an integer.

Where the initial amine is a bistertiary amine the correspondingmodification may be shown as ##STR4##

Similarly where the carrier was a halomethylated methylmethacrylate(crosslinking not shown) a modification of the invention may be shown as##STR5##

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The compositions of the present invention are prepared by activating acarrier to provide a labile center reactive with the tertiary amine ofchoice. In view of their physical characteristics their ready commercialavailability and comparatively low cost as well as their potential,under certain circumstances, to be regenerated, polymer resins form auseful class of carrier although the invention should not be consideredas limited thereto.

The majority of polymeric resins have a polystyrene backbone. A furtherreadily available although minor category of polymeric resin has amethacrylate backbone. The resins may be prepared in microporous ormacroporous structural form.

The most readily available polystyrene resins are crosslinked withcertain crosslinking agents among which the most common isdivinylbenzene (DVB), although again the invention is not considered tobe limited to the use of particular crosslinking agent.

The skeletal matrix of the resin, suitably of the DVB crosslinkedpolystyrene resin is then activated to provide a labile center whichwill react with the tertiary amine. An inexpensive and readily availablelabile group is the chloromethyl group. Chloromethylating agents and themode of reacting them with a polymeric skeletal matrix are well known inthe art. Indeed, chloromethylated DVB crosslinked polystyrene resin iscommercially available.

The chloro moiety of the chloromethyl group will provide the counterionof the quaternary ammonium salt ultimately produced. Thus, if it isdesired to utilize a counterion other than chloride, it can beintroduced later by simple and conventional ion exchange procedures.From the point of view of safety, the anion of any pharmaceuticallyacceptable acid may be utilized as the counterion. While, from the pointof view of safety any pharmaceutically acceptable anion may be employed,for example hydrochloric, hydrobromic hydriodic, sulphuric, phosphoric,nitric, acetic, propionic, lauric, benzoic, salicylic, cinamic, lactic,maloic, fumaric, pyruvic, glutamic, oxalic, methane sulphonic, benzenesulphonic, glucose-1-phosphoric, or the like, from the point of view ofeffectiveness halide, suitably chloride, bromide and iodide have beenfound to be totally effective in the tests for effectiveness which havebeen carried out are especially preferred.

The amine reagent utilized is a tertiary amine or a bistertiaryaminoalkane having the general structure ##STR6## R₁ and R₂ may be thesame or different and may be alkyl, alkenyl or cycloalkyl, suitablystraight or branch chain lower alkyl of one to eight carbon atomssuitably methyl, ethyl, propyl, isopropyl, butyl, n-butyl, isobutyl,pentyl, oxalyl or the like, straight or branch chain lower alkenyl oftwo to six carbon atoms such as ethenyl, propenyl, isopropenyl, butenyl,isobutenyl, tertbutenyl, pentenyl, hexenyl and the like or cycloalkyl ofthree to six carbon such as cyclopropyl, cyclobutyl, cyclopentyl orcyclohexyl. Also included are the corresponding cycloalkenyl moieties offour to six carbon atoms, either R₁ or R₂ may have the values of R₃below.

R₁ and R₂ may also be joined together to yield in conjunction with thenitrogen atom to which they are attached a heterocyclic moiety of fiveto seven atoms in the ring. This heterocyclic moiety may be saturated,partially unsaturated, or fully unsaturated that is to say aromatic.Included in this category would be aziridyl, pyrrolidyl, pyrrolyl,pyridyl, piperidyl, azepinyl, perhydroazopinyl and the like.

Of the foregoing, the pyridyl moiety is particularly preferred. Theforegoing heterocyclics may, if desired, be substituted by alkylmoieties appropriate to the R₁ and R₂ groups constituting the carbonportion of the hetrocyclic ring.

R₃ may be alkyl, suitably midalkyl of ten to sixteen carbon atoms whichmay be straight or branch chain, the former being preferred. R₃ may alsobe aryl, alkaryl, or aralkyl. The aryl moieties may be carbocyclic orheterocyclic, suitable carbocyclic, such as phenyl or naphthyl,similarly the alkaryl moieties may be carbocyclic or heterocyclic andare suitably substituted by lower alkyl substituents containing 1-5carbon atoms. These substituents may number from one to the maximumavailable number of positions on the ring. Thus, where the aryl moietyis phenyl, there may be from 1-5 substituents and where the aryl moietyis naphthyl there may be from 1-7 substituents; with respect to thearalkyl moieties, the aryl portion may be carbocyclic or heterocyclic,suitably carbocyclic, and may be substituted or unsubstituted phenyl ornaphthyl. The substitution is, suitably, by halogen or lower alkylmoieties of 1-6 carbon atoms located at from one to the maximum numberof available positions on the ring. Similarly, the alkyl segment of thearalkyl moiety is suitably lower alkyl of 1-6 carbon atoms.

The disinfectant compositions of the present invention in the form ofquaternary ammonium salts are prepared by reacting the amine of generalformula (IIIa) or (IIIb) above with the activated carrier, suitably theactivated cross-linked polymeric resin where the resin is a cross-linkedpolystyrene or cross-linked polymethylmethacrylate. Most suitably thereaction is carried out with commercially available chloromethylateddivinylbenzene cross-linked polystyrene.

In this procedure the activated polymeric resin is swelled prior toamination suitably by immersion in an excess of water miscible reactioninert organic solvent, suitably an alkanol, a ketone or a water miscibleether preferably a cyclic ether such as dioxane. The resin is immersed,suitably at ambient temperature, for from about 24 to about 60 hours.The mixture in the solvent is cooled to under about 5° C. suitably tobetween -10° C. to about +5° C. and an excess (based on active centerson the resin) of the amine of choice is added.

The amine is, suitably, pre-cooled to the temperature of theresin/solvent mixture. Where the amine does not dissolve readily in theswelling solvent upon agitation, the entire mixture is warmed justenough to permit solution of the amine, re-cooled to the aforementionedrange, and retained at that temperature for about 24 to about 60 hourssuitably for about 48 hours.

The aminated resin is then separated, suitably by filtration. It is heldin dilute acid suitably dilute mineral acid such as aqueous hydrochloricacid at ambient temperatures, suitably for from about 24 to about 60hours, and then washed alternately with aqueous acid and aqueous basesuitably dilute hydrochloric acid and dilute sodium hydroxide followedby aqueous saline and finally deionized distilled water in which it isstored.

The resulting material is then cycled in acid and base, suitably indilute aqueous hydrochloric acid and dilute aqueous sodium hydroxide,and then washed, first with several portions of dilute aqueous sodiumchloride and finally with deionized, distilled water until the effluentis free of chloride ion.

The quaternary ammonium salts in resin form prepared in accordance withthe foregoing procedures may be utilized to disinfect drinking water byany contact method known to the water purification art. The preferredmode, however, is to prepare a bed of the composition, suitably incolumn form, but not being restricted thereto, and causing the waterwhich is to be disinfected to pass through the column.

In accordance with accepted water purification techniques, it isdesirable to remove as much solid or colloidal material as possibleprior to contact with the resin. This may be done by any prefiltrationmethod known to the water purification art among which may be includedfiltration through sand, charcoal (in activated or other form), sinteredglass, glass fiber beds, or any other suitable and availableprefiltration medium. The material of the present invention is effectivenot only against bacteria and viruses, but also against fungi, algae andprotozoa.

Observations indicate that when a carrier bed loses its effectiveness asa disinfectant medium that loss is not due to chemical reactions or lossof reactive groups on the bed but rather to the blocking of the activesites by the debris of the biological material. The bed can therefore beregenerated by removing this absorbed microscopic debris from thesurface and interstices of the disinfectant composition.

It has been found that the resin may be regenerated by treatment withaqueous alkanolic acid, suitably with mixtures of ethanolic aqueoushydrochloric acid, suitably by utilizing between 6 and 12 N aqueoushydrochloric acid in an HCl-EtOH ratio of betwen 1:19 to 3:17. The modeof regeneration of the resin should not be considered to be limited tothis method.

The results of bactericidal tests carried out on a disinfectantcomposition within the scope of the present inventionN,N-dimethyldodecyl ammonium/(methylated/DVB crosslinked polystyrene)chloride are illustrated in FIG. 1. This test indicates that utilizing a1 ml bed of 0.8 cm² cross-section a total kill was noted up to anapplied level of 5.8×10⁷ microorganisms (viz: B. subtilis) In anotherexperiment no viable cells emerged from the bed until 8.2×10⁸ cells of atotal of 9.4×10⁸ cells had contacted the resin bed and thereafter lessthan 1% of the additionally applied bacteria emerged in viable form. Incontrast, where the parent polymer resin itself is utilized withoutquaternizing with the amine moiety, the percentage viability for between10⁷ and 6×10⁷ applied cells ranges from approximately 50% toapproximately 80%, indicating that some absorption but no realdisinfection occurs.

EXPERIMENTAL Preparation of Resin Material

Chloromethylated crosslinked polystyrene (5 g, 200-400 mesh, 2% divinylbenzene) is immersed in dioxane (250 ml) for 48 hours at ambienttemperature (ca. 20° C.). The mixture is cooled to 0° C. andN,N-dimethyl dodecyl amine (75 ml), precooled to 0° C. added. Themixture is warmed slightly to dissolve the amine and is then cooledagain and held at 0° C. for 48 hours with intermittent stirring. Themixture is filtered, the filtrate discarded and the residual resinsuspended in dilute aqueous hydrochloric acid (75 ml, 2 M) for 48 hoursat ambient temperatures. The resulting suspension is again filtered andthe resin washed with three cycles of aqueous hydrochloric acid (2 M, 50ml×3) and aqueous sodium hydroxide (0.1 M, 50 ml×3), thereafter withdilute saline (2 M, 25 ml×5) and with deionized, distilled water untilthe effluent is free of chloride. The resultant quaternary ammonium saltin resin form is stored in deionized distilled water.

In accordance with the above procedure, but where in place ofN,N-dimethyldodecyl amine there is utilized N,N-dimethyldecyl amine,N,N-dimethylmyristyl amine, N,N-dimethylbenzylamine,N-dodecyl-N-methyl-3,4-dichlorobenzylamine, quinoline, isoquinoline,pyridine N-N-didecylmethylamine, N-octyl-N-decylmethlamine,N-cetyl-N-dimethylnaphthylamine, a similar composition is obtained.

In accordance with the above procedure, but where in place of thetertiary amines set forth above there is utilized 1,10-bis(N,N-dimethylamino)decane or 1,2-bis(N,N-didodecylamino)ethane,there is obtained a similar product.

In accordance with the above procedure and using any of theaforementioned amines but utilizing the resins in macroporous form, asimilar product is obtained. Further, in accordance with the aboveprocedure but utilizing in place of a polystyrene resin a methylatedcrosslinked polymethylmethacrylate resin in macro porous or micro porousform there is obtained the corresponding product.

TEST PROCEDURES Preparation of Test Solutions

Bacillus subtilis (NP-40) was grown at 40° C. for 14-16 hrs in BufferedGlucose Broth. The cells were centrifuged at 24° C. (5000 rpm/7 min) ina Sorval Superspeed RC-2 Automatic Refrigerated Centrifuge. The pelletwas suspended in sterile Tris buffer (PH 7.6, 250 ml, 0.01 M). Samplesof this suspension (10 ml) were diluted with more buffer up to totalvolumes of 2000 ml. Prior to each experiment a control solution wasmaintained under identical conditions to the test solutions.

Preparation of Resin Bed

Resin prepared in accordance with Example 1 as well as control materialsi.e.(Dowex 1X2 and the parent chloromethylated divinylbenzenecrosslinked polystyrene) were slurried in deionized distilled water. 1ml of deionized distilled water was added to a 6 cm cm×0.8 cm² frittedglass column and the meniscus marked on the column. The slurried resinwas added so as to settle into a bed to the height of the mark. Theresin of Example 1 was utilized in chloride form except where indicatedto the contrary.

Test Method

The test solutions were run through the column at flow rates of between10 to 12 ml/min. Effluents were collected in 100 ml fractions atpredesignated intervals in 100 ml fractions (monitored at 200, 400, 800,1200, 1500, 1800, 1900, 2100 and 2300 ml points). Collection was insterile enclosed beakers. Portions of diluted and undiluted effluentwere plated out on Nutrient Agar and incubated overnight at 40° C.Thereafter the plates were examined for viable cells. The test resultsof various batches of the N,N-dimethyldodecyl ammonium/(methylated/DVBcrosslinked polystyrene) chloride of Example 1 are summarized in Table Ibelow.

Comparative tests with the chloromethylated divinylbenzenepolystyreneresin itself (i.e. without quaternization) or with the chloride form ofa polystyrene benzyltrimethyl ammonium ion exchange resin (Dowex 1 type)show no anti microbial activity although in preliminary experiments aslight reduction in the number of viable cells is noted due to a"filtration " effect.

Effect of Other Counterions

The chloride counterion of the principle composition of Example 1 wasdisplaced with the following ions: bromide, iodide, thiocyanate,ethanesulfonate, n-pentane sulfonate by passing an aqueous solution ofthe corresponding sodium salt through the column.

Test experiments in accordance with the foregoing procedures bututilizing an application of 1600 ml of test solution containing 2.4×10⁹cells of B. subtilis per charge yielded the following proportion ofviable cells in the last 100 ml fraction.

Bromide: 0

Iodide: 0

Thiocyanate: 33%

Ethanesulfonate: 10%

N-pentane sulfonate: 1%

The resin, after exhaustion (arbitrarily defined as 50% viable of B.subtilis organisms to pass therethrough) was regenerated by passingthrough the column a mixture of aqueous hydrochloric acid (12N) andethanol in a ratio of both 1:19 and 2:9 followed by sterile Trishydrochloride buffer (pH 7.6, 250 ml, 0.01 M). The regenerated columnswere then resubjected to passage of B. subtilis suspension as set forthabove.

The results are summarized in FIG. 2.

                  TABLE I                                                         ______________________________________                                        Kill Capacity of Resin 12                                                     Temper-                                                                              Resin   Amount                 % Viable                                ature  Batch   Cells Applied                                                                              Kill Capacity*                                                                          of Total                                ______________________________________                                        24° C.                                                                        1     a     9.4 × 10.sup.8 /2300 ml                                                            8.2 × 10.sup.8                                                                    <1                                                 b     same       same      same                                  35° C.                                                                        1     a     9.6 × 10.sup.8 /1800 ml                                                            ≧total                                                                           0                                                  b     same       same      same                                  24° C.                                                                        2     a     9.4 × 10.sup.8 /2300 ml                                                            ≧total                                                                           <1                                                 b     same       same      same                                  24° C.                                                                        3     a     2.4 × 10.sup.9 /1600 ml                                                            ≧total                                                                           0                                                  b     same       same      same                                  ______________________________________                                         *Operationally defined as the total number of cells applied to first          appearance of viable cells in column effluent.                           

We claim:
 1. A water insoluble disinfectant composition comprising aquaternary ammonium salt of the formula: ##STR7## wherein a is apositive integer, n is an integer of 1-6, Q is a water insoluble crosslinked resin of microporous or macroporous structure selected from thegroup consisting of polystyrene resins having methylene moietiesattached to the backbone thereof, and polymethyl methacrylate resins, Xis the anion of any physiologically acceptable salts, and Z is ##STR8##wherein R₁ and R₂ are selected from the group consisting of straight orbranch chain lower alkyl of one to eight carbon atoms, straight orbranch chain lower alkenyl of two to eight carbon atoms, lowercycloalkyl of three to six carbon atoms and taken together with thenitrogen to which they are attached, form a saturated or unsaturatedheterocycle having five to seven carbon atoms in the ring, R₃ isstraight or branch chain midalkyl of ten to sixteen carbon atoms,phenyl, halo or lower alkyl substituted phenyl, naphthyl lower alkyl andhalo or lower alkyl substituted naphthyl lower alkyl wherein said loweralkyl moieties are of one to five carbon atoms and are substituted onfrom one to five positions on the phenyl nucleus and from one to sevenpositions on the naphthyl nucleus, R₄ and R₅ are selected from the samegroup of values as R₁ and R₂, y is a positive integer of 1-20, providedthat where R₁, N, and R₂ are joined to form a fully unsaturedheterocycle, R₃ is absent and Z is bonded to the methylene moieties. 2.A composition of claim 1 wherein Z contains at least one heterocyclicgroup.
 3. A composition according to claim 1 wherein the resin comprisesa polystyrene or a methacrylate backbone.
 4. A composition according toclaim 3 wherein the resin is a divinlybenzene crosslinked polystyreneresin.
 5. A composition according to claim 3 having methylene moietiesattached to the resin backbone said methylene moieties being bonded tothe ammonium nitrogen.
 6. A composition according to claim 1 wherein Zis pyridinium, quinolinium or isoquinolinium.